Thanks to the folks at Hunter Marine, they told me there's a nut holding the screw on the track end cap (access is from inside the cabin). Don't use the "gorilla" solution that I was first going to use.Here's how I did it. These directions apply to 386's with a "soft interior headliner".On the inside of the cabin, I removed the frame around the port closest to where I thought the bolt might be (over the sink/refrig area). Then, remove half of the staples holding the headliner. Reach in and gain just enough hand room to locate and undo the nut. It's size is 13mm. Remove the nut then go to the outside and unscrew the bolt and replace the track stop. Return to the cabin and replace the nut, tighten and restaple the headliner. Replace the port frame and you're done.